#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
#include <unordered_map>
#include <unordered_set>
#include <string>

class Graph {
 private:
    int size_g;
    std::vector<std::vector<bool>> data;
    std::vector<int> used;

 public:
    std::vector<bool> isused;

    Graph() {
    }

    explicit Graph(int n) {
        data.resize(n);
        size_g = n;
        for (int i = 0; i < n; i++) {
            data[i].resize(n);
        }
        isused.resize(n);
    }

    void insert(int a, int b) {
        data[a - 1][b - 1] = true;
        data[b - 1][a - 1] = true;
    }

    void subgraph2(int a) {
        if (!isused[a - 1]) {
            isused[a - 1] = true;
            used.push_back(a);
            for (int i = 0; i < size_g; i++) {
                if (data[a - 1][i]) {
                    subgraph2(i + 1);
                }
            }
        }
    }

    std::vector<int> subgraph(int a) {
        used = {};
        subgraph2(a);
        return used;
    }
};

int main() {
    int N, M;
    int a, b;
    std::cin >> N >> M;
    if (N != 0 && M != 0) {
        Graph graph(N);
        for (int i = 0; i < M; i++) {
            std::cin >> a >> b;
            graph.insert(a, b);
        }
        std::vector<std::vector<int>> result;
        for (int i = 0; i < N; i++) {
            if (!graph.isused[i]) {
                result.push_back(graph.subgraph(i + 1));
            }
        }
        std::cout << result.size() << '\n';
        for (int i = 0; i < result.size(); i++) {
            std::cout << result[i].size() << '\n';
            std::cout << result[i][0];
            for (int j = 1; j < result[i].size(); j++) {
                std::cout << " " << result[i][j];
            }
            std::cout << '\n';
        }
    } else if (N == 0) {
        std::cout << 0;
    } else {
        std::cout << N << '\n';
        for (int i = 0; i < N; i++) {
            std::cout << 1 << '\n' << i + 1 << '\n';
        }
    }
}